The present invention relates to a portable radio terminal such as a radio pager, and more particularly, to a radio portable terminal having a protection function of preventing deletion of a received message stored in the terminal.
A portable radio terminal, such as a radio pager, has a function of storing a received message. Since the number of messages which the radio terminal can store is finite, if the radio has received messages in excess of the storage capacity, the messages are automatically deleted in chronological order of receipt. Even if the user desires to have an important received message retained, the message will eventually be deleted, so long as the radio terminal continues to receive new messages. To prevent such a problem, the radio terminal is provided with a function of protecting received messages, thus enabling the user to designate important received messages desired for retention. If all messages which the radio terminal can store are protected, the radio terminal becomes unable to receive any new messages. For this reason, the number of protected messages is inevitably set to a number which is smaller than the maximum number of received messages to be stored. The maximum number of messages which can be protected will be hereinafter referred to as the "maximum protection number."
In an existing portable radio terminal, procedures for designating a received message a message to be protected will be described by reference to a block diagram shown in FIG. 1, which illustrates the configuration of-a pager system, as well as by reference to a flowchart regarding an existing message protection function shown in FIG. 3. First, the pager system changes to a message read mode by pressing a rotary switch 4 while the pager system is in a wait mode (SET step). An arbitrary message to be protected is selected (STEP 1) by rotating the rotary switch 4 (SLCT step). The pager system changes to a mode selection screen state by pressing a switch 5 while the thus-selected message is indicated on a display (MODE step), so that a protect/protect-cancel guidance message is displayed (STEP 2). In a case where the selected message has a protection attribute, a protect-cancel verification message is displayed together with the selected message by pressing the rotary switch 4 while the guidance is displayed (SET step). In contrast, if the selected message does not have a protection attribute, a protect verification message is displayed together with the selected message (STEP 3). When the rotary switch 4 is pressed while the message is displayed (SET step), a decision is made as to whether or not the message has a protection attribute (STEP 4).
In a case where the selected message does not have a protection attribute, if the current protect operation will cause the number of protected messages to exceed the maximum protection number as a result of a decision as to whether or not the maximum protection number is exceeded (STEP 5), a warning about exceeding the maximum protection number is displayed (STEP 6). Subsequently, the pager system changes to a state in which a protect verification message is displayed together with a selected message (STEP 3) as a result of a timeout occurring for one second (MODE step) or the rotary switch 4 (SET step) or the switch 5 (MODE step) being pressed. When the rotary switch 4 is rotated while the message is displayed (SLCT step), messages stored in the pager system are displayed in chronological order of receipt without regard of presence/absence of a protection attribute. From the thus-displayed messages, the user selects a message which has a protection attribute and is deemed to be least necessary. When the rotary switch 4 is pressed (SET step) while the selected message is displayed, a decision is made as to whether or not the message has a protection attribute (STEP 4). In this case, since the selected message has a protection attribute, the pager system cancels the protection of the message and decrements the current number of messages to be protected (STEP 10), thus displaying completion of the protect cancel operation (STEP 11). After the message regarding completion of the protect cancel operation has disappeared as a result of a timeout occurring for one second or the rotary switch 4 (SET step) or the switch 5 (MODE step) being pressed, an unprotected message is displayed (STEP 9). Simultaneously, the pager system returns to the message read mode.
A message originally desired to be protected is selected once again by rotating the rotary switch 4 (SLCT step) (STEP 1). When the switch 5 is pressed while the selected message is displayed (MODE step), the pager system changes to a mode selection screen, where the protect/protect-cancel guidance is displayed (STEP 2). When the rotary switch 4 is actuated (SET step) while the guidance is displayed, a protect verification message is displayed together with the thus-selected message (STEP 3). When the rotary switch 4 is pressed (SET step) while the message is displayed, a decision is made as to whether or not the message has a protection attribute (STEP 4).
Since the message does not have any protection attribute, a decision is made as to whether or not this protecting action will result in the number of protected messages exceeding the pager system's maximum-protection number (STEP 5). Since the message is unprotected and hence the maximum protection number is not exceeded, the number of protected messages is incremented (STEP 7), and a protection completed message is displayed (STEP 8). After the protection completed message has disappeared as a result of a timeout occurring for one second or the rotary switch 4 (SET step) or the switch 5 (MODE step) being pressed, the protected message is displayed with a protection-attribute mark (STEP 9). Simultaneously, the pager system returns to a message read mode (STEP 1).
If the user attempts to protect a new message while the number of protected messages is equal to the maximum protection number, the existing procedure mentioned previously requires the user to retrieve a message whose protection may be canceled from all the received messages, including received messages having no protection attribute, as well as to cancel the protection of the thus-selected message or to delete it. Further, the existing procedure requires the user to retrieve a message originally desired to be protected and to protect it. Thus, the existing procedures involves complicated key operations. Accordingly, the object of the present invention is to render simple an operation for protecting a message while the number of protected messages is equal to the maximum protection number.